The present invention relates to a motor-driven compressor, and more particularly to a motor-driven compressor that has a compression mechanism, an electric motor and an inverter aligned in the order in axial direction of the compressor.
A conventional motor-driven compressor is disclosed in Japanese Unexamined Patent Application Publication No. 2000-291557. The compressor has a compression mechanism, an electric motor and an inverter aligned in the order in axial direction of the compressor. The interior of the compressor housing is divided into two spaces by a partition wall. The electric motor is accommodated in one of the spaces, while the inverter is accommodated in the other space. The compressor further has a hermetic terminal provided on the partition wall for electrically connecting the electric motor and the inverter The electric motor and the inverter are electrically connected to the hermetic terminal.
In the above-described compressor, the electric motor and the hermetic terminal are electrically connected through a motor harness extending from the coil end of the electric motor. It is desired to reduce the length of such motor harness in order to prevent the motor harness from being pinched between the parts in assembling the compressor and also from interfering with the moving parts of the compressor such as the drive shaft and the rotor. Therefore, the coil end of the electric motor connected to the motor harness is generally located on the side of the inverter so that the length of the motor harness is set to minimum. In such a case, however, the motor harness of small length needs to be connected to the hermetic terminal in a narrow space between the electric motor and the partition wall in assembling the compressor, which makes it difficult and troublesome to perform the connection between the motor harness and the hermetic terminal. That is, the time required for such connection is increased in assembling the compressor, and manufacturing cost of the compressor is increased, accordingly.
The axial length of the coil end of the electric motor on the side of the compression mechanism, that is, on the opposite side from the motor harness is smaller than the axial length of the coil end on the side of the inverter, that is, on the side of the motor harness. On the other hand, there is an empty space around the shaft support of the compressor where the bearing is mounted for rotatably supporting the drive shaft. If the coil end located on the side of the compression mechanism can be provided in the empty space, the axial length of the compressor is reduced. In such a case, however, the position of the electric motor cannot be moved in such a way that such coil end is provided in the empty space. This is because the rotor has generally balancers at the opposite ends thereof for reducing the vibration generated by the rotating drive shaft and rotor, and the balancer on the side of the compression mechanism is located in opposing relation to the bearing described above. That is, the electric motor having the coil end connected to the motor harness on the side of the inverter makes it difficult to reduce the axial length of the compressor for downsizing.
The present invention is directed to providing a motor-driven compressor of reduced manufacturing cost and reduced size.